Two-cycle diesel engine



Nov. 12, 1940.,,

TWO-CYCLE DIESEL ENGINE Filed Oct. 7, 1939 B'Sheets-Sheei 1 B. A. SWANSON 2,221,156

Nov. 12,1940. 3 ALSWANSQN 2,221,156

TWO-CYCLE DIESEL ENGINE .Filed dct. 7, 1939 2 Sheets-Sheet 2 Wang Patented Nov. 12, 1940 UNITED STATES PATENT OFFICE I TWO-CYCLE DIESEL ENGINE Bernard A. Swanson, Port Angeles, Wash) Application October 7, 1939, Serial No. 298,497 11 (01. 123-34) This invention relates generally to the class of internal combustion engines and pertains particularly to a Diesel type two-cycle engine.

The primary object of the present invention is to provide in a two-cycle engine of the Diesel type, a novel construction in which compressed air is provided by the piston of the engine and supplied to the liquid fuel receptacle to efiect the movement of fuel into a vaporizing chamber of the engine and such compressed air is also employed as a scavenging medium and to supply the necessary oxygen to the engine cylinder for the proper. combustion of the introduced fuel.

Another object is to provide in a Diesel type of engine, a novel fuel injector mechanism whereby a regulated charge of fuel may be introduced under high pressure into the engine cylinder at the proper period in the movement of the piston in the cylinder.

A further object is to provide a novel twocycle Diesel type engine which is so constructed and arranged that a material reduction in the number of moving parts is made over what is required in engines of this type which are at present in use, and a completely closed system of lubricant feed and fuel feed is employed which effectively'eliminates the danger of fire.

The invention will be best understood from a consideration of the following detailed description taken in connection with the accompanying drawings forming part of this specification, with the understanding, however, that the invention is not to be confined to any strict conformity with the showing of the drawings but may be changed or modified so long as such changes or modifica tions mark'no material departure from the salient features of the invention as expressed in the appended claims.

In the drawings:

Fig. l is a view in vertical section through a single cylinder form of Diesel engine constructed in accordance with the present invention, the

lubricant receptacle and fuel receptacle being Fig. 7 is a viewin bottom plan of the engine I piston.

Fig. 8 illustrates a modification of the injectorunit shownin section in Fig. 1.

Referring now more particularly to the draw- 5 ings, it is to be understood that while there has been illustrated only a single cylinder engine, it is withinthe scope of the present invention to apply the same to a multiple cylinder engine.

The numeral I generallydesignates the cylinder block in which is formed the cylinder 2, which has the solid head 3, the water jacket 4 which surrounds the cylinder, and an air chamber 5 which also encircles the cylinder and which opens thereinto through the port 6.

Theportion of the engine block or body lying above the head 3 of the cylinder has formed on its exterior surface the baflie fins I and covering this top part of the engine block is a cap 8 which forms with the top of the engine block a fuel vaporization chamber 9, the top wall of the cap having downwardly extending baflle fins I 0 which cooperate with the fins I to form a tortuous passageway from one side of the cap to the other for fuel vapors which enter the chamber 9 at the port I I and pass out therefrom through the port I2.

The cylinder head 3 is preferably inclined as illustrated and has a threaded opening I3 formed therethrough which registers with a similar opening formed in the central part of the cap it for the reception of the threaded nozzle end I4 of an injector unit which is indicated generally by the numeral I5. This injector unit includes a 35 sleeve body I6 at one end of which the nozzle I4 is formed, which houses an injector plunger II, the sleeve being vertically arranged as shown. The nozzle at its discharge end has a number of spray apertures l8 and at the inner side 01. these 40 apertures. is an outwardly opening ball check valve constituting a ball seat I9 and a ball 20.

At one side of the sleeve I6 there is formed a cylinderZI which is horizontally disposed or is perpendicular to the sleeve I6 and which houses 45 a piston 22 which carries the stem 23. Exteriorly of this cylinder 2I a spring 24 connects the outer end of the piston stem with the body of the cylinder and normally tends to pullthe piston 22 away from the sleeve I 6. At the inner end of 50 the cylinder 2I a fuel passage is formed as indicated at 25, which leads from the cylinder into the lower part ofthe sleeve I6 beneath the lower end of the plunger II, this fuel passage being controlled by the check valve 26 which opens outwardly from the cylinder and toward the lower end of the sleeve.

The cylinder 2| is connected with the outlet port l2 for the fuel vaporization chamber 9 by the pipe line 21 in which is located a. valve 29 by means of which the flow of vaporized fuel through the pipe may be controlled.

The plunger extends upwardly through the upper end of the sleeve "5 as shown in Fig. 1 and has connected between its outer end and the adjacent end of the sleeve, the expansion spring 29 which normally urges the plunger to move outwardly or away from the discharge end of the nozzle.

The cap 8 supports, through the medium of a suitable standard such as is indicated at 30, a horizontal rock shaft 3| on which is oscillatably mounted a bell crank 32 having a push rod arm 33 and a second arm 34 which rocks in a vertical plane in which the piston stem 23 lies and is spaced from the outer end of this stem and cartacts the stem to force the piston 22 inwardly.

Freely rockable on the rock shaft 3| but adapted to be actuated by. the: push rod arm 33 is a plunger actuating lever 36, the free end of which overlies and contacts the outer end of the plunger H. The upward movement of this lever under the action of the plunger moving spring 29 is controlled by an eccentric disk 31 which is pivotally eccentrically supported by trunnions 38 upon the upper end of a supporting arm 39 which forms a part of the standard 30. The eccentric disk 31 overlies and bears against the top edge of the lever. 36 and is adapted to be rocked to a desired adjusted position by means of the upwardly extending finger .piece 49 which may be coupled with a suitable control rod for operation from a remote point.

The lower part of the cylinder block is supported upon and is secured to a base block 4| which covers and closes the lower end of the cylinder, being provided with a suitable gasket as at 42, to establish an air-tight connection with the cylinder block. The central part of this base block is'formed to provide a crank chamber 43 which also constitutes a compressed air chamber. The base block supports alined bearings 44 through which are extended the ends of a crank shaft 45, the intermediate portion'of the shaft being shaped to form a crank 46 which swings on the longitudinal center of the cylinder and down into the chamber 43. One end of the shaft supports the usual fly wheel 41.

Within the cylinder is disposed a piston 49 having the inclined or sloping head 49 which corresponds in its inclination to the inclination of the cylinder head} and which at its high side is provided with the laterally and upwardly open- 7 ing pocket 59 which, when the piston is at the limit of its outward movement in the cylinder, comes into register with the air inlet port 6. Opposite the air inlet port 6 and uncovered by the piston when it is at the limit of its movement outwardly is an exhaust port 5| which connects with a suitable exhaust pipe 52.

The piston is of hollow construction but is closed at its bottom by the wall 53, the central part of this wall being shaped to form the inwardly extending casing 54. This casing 54 encircles the wrist pin 55 which extends inthe usual manner transversely through the piston and has connected with it the upper end of the usual connecting rod 56.

The skirt portion of the piston has oppositely disposed ports 5'! and 58 formed therethrough and there is formed through the cylinder block an air admission port 59 which draws air from the exterior of the cylinder through a suitable filter 60 and which registers with the piston port 51 when the piston is at the limit of its movement inwardly in the cylinder. When the piston is in this position of limited inward movement, the port 58 of the piston skirt registers with the upper end of a by-pass passage 6| which opens into the cylinder and which has a lower end which is positioned so that it will discharge into the cylinder beneath the piston when the piston is at the limit of its inward movement. Thus it will be seen that asthe piston moves inwardly in the cylinder and thus creates a condition of reduced atmospheric pressure beneath it and in the chamber 43, air from the outside will be drawn in through the air filter and the port 59 and across the interior of the piston when the ports 51 and 59 register and will pass from the port 59 into the by-pass passage 6| and then downwardly into the cylinder below the piston. On reverse movement of the piston when it is moving outwardly from the cylinder, this air willbe compressed in the chamber 43 and discharged therefrom as hereinafter stated.

The crank shaft bearings 44 have oil channels formed therein as indicated at 63, and the crank shaft has an oil passage 64 extending longitudinally therethrough from one channel 63 to the other and this passage passes through the crank 46 as shown, and has a lateral outlet which communicates with a passage 65 running lengthwise through the connecting rod 56.

The wrist pin 55 is provided with a longitudinally extending oil passage 66 which has a central lateral opening which communicates with the connecting rod passage 65 and other lateral openings which are indicated at 61 which lead to discharge or spray nozzles 69 which are carried within the upper .part of the piston and directed toward the underside of the Fig. 1.

The chamber 43 has a discharge opening 69 which is controlled by the outwardly opening valve 19 and this discharge opening communicates with the conduit II which leads into the lubricating oil receptacle 12 which is air-tight. The filling opening for this receptacle is closed by the cap 13. From within the oil receptacle there extends the oil conducting pipe 14 which leads to an oil recess 63 which is formed in a bearing around the crank shaft and the inner end of this oil pipe or tube carries a strainer of suitable design as indicated at I5. Thus it will be seen that air pressure developed in the receptacle 12 will tend to force oil through the pipe 14 and into the oil distributing passages in the crank shaft, connecting rod and wrist pin, the oil flowing into the wrist pin discharging from the ends thereof against the cylinder wall and from the nozzles 68 into the cylinder to be drained back into the chamber 43 by way of the outlet apertures 16 which are formed through the skirt of the piston near the bottom thereof.

An oil collecting groove is formed around the crank shaft outwardly of a distributing channel 63, as indicated at I1 and this communicates by way of an outwardly opening valve 18 with a drain tube 19 which leads at an inclination through the base block of the engine into the crank case or compressed air chamber. At the opposite side of the connecting rod from the oil collecting channel 11 a similar drain tube 88 is formed which leads from a cam housing 8| which is formed in the base block, the end of the tube 88 being normally closed by the valve 82 which opens outwardly from the, cam housing 8|. By means of these tubes I9 and 68, any oil which may work past the oil channels 63 is drained back to the receptacle I2 through the chamber 43, the inward movement of the piston creating sufficient reduced pressure in the tubes to draw the oil into the chamber 43 and the outward movement of the piston ejecting the oil past the valve I8 and into the oil receptacle. I

Within the cam housing M is a cam 83 which is carried upon the crank shaft. Extending into the upper part ofthe cam housing is a guide sleeve 84 which as shown, is secured to the base block, in which is reciprocably supported a cam follower 85. An arm 86 which is secured to the base block over and in spaced relation from the follower 85, holds an expansion spring 81 which bears against the follower and extendingthrough this arm and through the expansion spring to rest at its lower end on the follower is a push rod 88, the upper end of which is pivotally connected with the push rod rock arm 33. Thus it will be seen that as the crank shaft rotates, the cam 83 will raise and lower the push rod 88 and as the rod lowers, the arm 34 will force the piston 22 forwardly in its cylinder. This piston operates in the nature of a fuel pump, ejecting a charge of fuel from its cylinder into the nozzle of the injector sleeve I6 and, when it moves outwardly under the action of the spring 24, as the push rod moves upwardly, drawing another charge from the vaporization chamber 8 through the pipe 21. As the push rod moves up, the lever 36 will be depressed, thus moving the plunger I'I downwardly and injecting the fuel charge from the nozzle into-the engine cylinder.

The numeral 89 designates the fuel receptacle which is divided into a lower fuel chamber 98 and an upper air chamber 9I. The lower chamber of the fuel receptacle receives air under pressure from .the upper part of the oil receptacle I2 by way of the pipe 92, through the one-way inlet valve 93. The filling pipe for the lower chamber of the fuel receptacle is indicated at 94 and extends through the air chamber as shown, the upper end being closed by the cap 95. A spring pressed valve 96 closes a port formed through the wall of the pipe 94 and leading into the air chamber 9|, this spring pressed valve being tensioned by the adjusting screw 91. Thus it will be seen that air under suificient pressure will flow past the valve '96 into the compressed air chamber 9|.

Leading from the lower chamber 98 or fuel containing portion of the receptacle 89 is a fuel outlet pipe 98 which at its lower end has a suitable filter 99 through which the fuel passes before entering the vaporization chamber 9 and the other end of this pipe connects with the inlet port II of the chamber 9, as shown.

Leading from the compressed air chamber 9| is an air conducting pipe I88 which discharges into the air chamber 5 which encircles the engine cylinder.

In Fig. 8 is illustrated a slightly modified form of the injector unit I5. This modified form of the injector which is generally indicated by the numeral 'I8I employs a plunger I82 mounted in a sleeve I83 and a piston I84 slidably supported in a cylinder I85 which is disposed at right angles to the sleeve I83, these parts being of the same construction and arrangement as the parts shown which leads from the vaporization chamber 9 of the engine whenthis ejector is threaded in the opening I3 in the head of the engine. However, in the modified form of the injector, the passage leading from the cylinder I85 into the sleeve I83 below the plunger I82, and which is indicated by the numeral I81, leads upwardly or vertically through a port I88, the upper side of which is formed to provide a valve seat I89 for a ball check valve I I8 and above the ball check a lateral port III opens into the sleeve I83.

The lower end of the sleeve I 83 is formed to provide the exteriorly threaded head II2 which engages in the cylinder head opening I3 and within this head I I2 is removably secured a nozzle II3 which supports a ball check valve II4, which check valve is adapted to close the discharge port I I5 leading from the sleeve I83, under the urge of back pressure from the engine cylinder.

The wall of the piston cylinder I85 has a longitudinally extending relief passage II6 formed therein which at one end opens into the fuel line I86 while its other end opens through the port I I1 into the cylinder I85 adjacent the end thereof remote from the piston I84. This port II'I which operates as a relief port is closed by the outwardly opening ball check I I8 which is normally pressed into seating position by the spring II9 which is held at an adjusted tension by the adjusting screw I28 which is threaded into the body of the wall of the sleeve I83.

By this modified form of injector there is built up in the vaporizing chamber a pressure when the motor is idling whereby when it is desired to speed up the operation of the motor such increase of speed may be accomplished more readily due to the fact that the fuel vapor, being under pressure, will flow more rapidly. tothe injector unit for discharge into the engine cylinder. It will, of course, be readily understood that in this modification the plunger I82 will be actuated by the finger 36 and the piston I84 will be actuated by the arm 34 and that upon the forward or working stroke of the piston I84 fuel vapors, previously drawn into the cylinder I85 by the outward movement of the piston I84, will be forced past the ball check II8 into the sleeve beneath the plunger I82, and that on the downstroke of the plunger by the finger 36, this fuel vapor will be forced through the spray head I I3 into the engine cylinder, the ball check II8 meanwhile seating itself and preventing the vapors from passing back into the cylinder I85. When the engine is idling surplus pressure built up in the cylinder I85 by the piston therein will escape through the bypass passage H6 and past the ball check II8 to be forced back into the vaporization chamber 9 through the pipe I86.

As previously stated, although only a single cylinder form of the present invention has been illustrated and described, it is to be understood that the invention may be readily carried out in an engine having a. number of cylinders and when a multi-cylinder engine is constructed in accordance with the present invention, there will be provided air and oil-tight partitions between the crank casings or compressed air chamb s 43 so that each cylinder will operate in efiect as an engine independent of the other cylinders.

From the foregoing, it is believed that the op-' eration of the present engine will be readily apparent. It will be seen that during the engine operation the piston 48 on its downstroke will compress air in the chamber 43 which will be passed through the passage II into the oil receptacle 12 passing from here into the lower part of the fuel receptacle 89 and from there by way of the valve 95 into the compressed air chamber 9|. The air pressure in the oil receptacle 1! will force the oil upwardly through the pipe 14 into the lubricating channel 63 from where it will flow through the passage 64 into the distributing passages in the body of the piston. The oil will be discharged from the nozzles 88 in the body of the piston and will find its way back to the oil receptacle by way of the drain apertures 16 in the skirt of the piston and the compressed air chamber or crank case 43. Oil working along the crank shaft will be checked I i! caught at one end in the annular channel 11 and at the other end in the cam housing 8i and will flow back through the passages 19 and 80 into the air chamber 43 from where it will be forced back by the compressed air into the receptacle I2.

When the piston is at the lowermost limit of its stroke or at the outward limit of its movement, the air discharge port 6 will be opened by said compressed air chamber to receive air unthe piston recess allowing compressed air to pass from the receptacle 9| through the pipe 180 into the air chamber 5 and out through the port 6 into the interior of the engine cylinder. Products of combustion remaining from a previously exploded fuel charge will escape by way of the outlet or exhaust port 5!.

As the piston moves inwardly, the ports 6 and 5| will be closed and a decreased pressure will be established beneath the piston in the air chamber 43 with the result that when the port 51 in the skirt of the piston registers with the air inlet port 59, air will flow into the piston and across it to the port 58 and from there through the passage 6| to the underside of the piston so as to equalize the pressures beneath the piston and outside of the engine cylinder.

As the piston moves upwardly it will compress the air introduced through the port 6 to a high degree, thereby raising the temperature of the air as is customary in Diesel engine operation, and

when the piston has reached the limit of its inward stroke, the cam 83 will raise the rod 88 so as to force the plunger i'I inwardly and thus inject a charge of fuel previously introduced into the plunger sleeve by the piston 22. Ilfpon downward movement of the rod 88, the piston 22 will be forced inwardly to inject a new charge into the plunger sleeve and when the piston is released by the arm 34, it will move outwardly under the action of the spring 24 so as to draw into the cylinder 2| a new charge of vaporized fuel from the vaporization chamber 9. The length of stroke of the plunger Il may be regulated within certain limits by the cam 3'! which is adjusted in the manner previously described.

What is claimed is:

l. A two-cycle Diesel engine of the character described, comprising a piston cylinder, a piston in the cylinder, means forming'a closed air chamber at the lower end of the cylinder, a crank shaft with which the piston is operatively coupled, means for admitting air to the cylinder beneath the piston when the latter is at the full inward extent of its stroke, the piston operating to compress air beneath it upon its downstroke, a fuel receptacle, an air receptacle means for conducting air under pressure from beneath the piston into said receptacles, means for admitting air under pressure from the air receptacle into the cylinder when the piston is at the limit of its outward stroke, a fuel vaporizing chamber formed over and as a part of the head of the cylinder, the chamber receiving fuel under pres sure from the receptacle, an injector unit for the cylinder constructed and arranged to receive vaporized fuel from said vaporizing chamber, and means for actuating the injector unit to discharge fuel into said cylinder.

2. A two-cycle Diesel engine, comprising a cylinder, a piston therein, means forming an air chamber about the cylinder, means closing the lowerend of the cylinder and forming a compressed air chamber therewith, a crank shaft operatively coupled with the piston, said piston iii-moving outwardly in the cylinder operating to compress air in said last chamber, means for admitting air into the cylinder beneath the piston when the piston is at the limit of its inward stroke and conducting such air through the body of the piston whereby to cool the latter, said first air chamber having an inlet port whichis uncovered by the piston at the limit of its outward stroke, a fuel receptacle connected with der pressure therefrom, means forming a fuel vaporization chamber upon the head of the cylinder to be heated thereby, means for conducting fuel from the receptacle into said vaporization chamber, said receptacle being formed to provide a compressed air chamber and having valve means for admitting air from the fuel receptacle thereinto, means for conducting air from said last compressed air chamber into the air chamber encircling the cylinder, the cylinder having an exhaust port uncovered by the piston at the outward limit of its stroke, means in the head of the cylinder for receiving vaporized fuel from the vaporization chamber, and means operated by the crank shaft for forcibly injecting fuel from the said receiving means into the cylinder.

3. A two-cycled Diesel engine, comprising a cylinder, a piston therein, a crank shaft operatively coupled with the piston, means for admitting air into the cylinder beneath the piston when the latter is at the inward limit of its stroke, means forming a compressed air chamber beneath the piston in which admitted air is compressed by the piston on its outward stroke, a cap secured over the head of the cylinder and forming in association therewith a fuel vaporization chamber, means for effecting the introduction of fuel into the vaporization chamber by air compressed by said piston, means for introducing air under pressure from the underside of said piston through the wall of and into the cylinder when the piston is at the limit of its outward stroke, the cylinder having an exhaust port which is uncovered by the piston at the limit of its outward stroke, an injector unit having a vaporized fuel receiving sleeve which is in communication at one end with the cylinder, means for conducting fuel from the vaporization chamber into said sleeve, and means for electing the vaporized fuel from the sleeve into the upper part of the cylinder.

4. A two-cycle Diesel engine, comprising a cylinder, a piston therein, a crank shaft operatively coupled with the piston, means closing the lower end of the cylinder providing an air compression chamber, means for admitting air to the lower part of the cylinder when the piston is at the limit of its inward stroke, the piston operating upon outward movement to compress the air in the chamber, a pair 'of fluid receptacles. for the reception of lubricating oil and liquid fuel, one of said receptacles receiving air under pressure from said chamber, means for conducting air under pressure from the'said one recptacle to the other receptacle, means for conducting lubricating oil under air pressure from the lubricant receptacle to moving parts of the engine, a fuel vaporization chamber arranged to be heated by the engine cylinder, means for conducting fuel'under air pressure from the fuel containing receptacle to said vaporization chamber, means operated by said crank shaft for withdrawing fuel from the vaporization chamber and injecting it into the upper part of the cylinder, an air inlet port for the cylinder, means for conducting air under pressure from one of said receptacles to said air inlet port, and an exhaust port for the cylinder, said inlet and exhaust port being uncovered by the piston when the latter is at the limit of its outward stroke. A

5. In a Diesel engine, a piston cylinder, a piston within the cylinder, a crank shaft operatively coupled with the piston, a cap secured over the head of said cylinder and cooperating therewith to form a fuel vaporization chamber, an air compressing means, a fuel receptacle, means for discharging fuel from the receptacle by air received from the compressing means into the fuel vaporization chamber, the engine cylinder having an air inlet port, means for conducting air under pressure from said compressor means to said air inlet port, an exhaust port for the cylinder, said inlet and exhaust ports being uncovered by the piston when at the limit of its outward stroke, and means for injecting fuel into the cylinder operated by said crank shaft and comprising a body having a pair of chambers, one of said chambers being connected with said vaporization chamber and the other body chamber being in communication with the interior of the cylinder, means in the first one of said pair of chambers for drawing fuel thereinto from the vaporization chamber and for introducing the fuel into the second chamber, and means in said second chamber for forcibly ejecting the fuel therefrom into the engine cylinder.

6. In a Diesel engine including a cylinder, a piston therein, and a crank shaft operatively coupled with the piston, means for introducing air into the cylinder when the piston is at the limit of its outward stroke, means for exhausting products of combustion from the cylinder when the piston is at the limit of its outward stroke, a fuel injector unit comprising a body formed to provide a sleeve and a perpendicularly disposed cylinder, means for connecting an end of said sleeve with the interior of the engine cylinder, an injector plunger in said sleeve, a valved passage connecting said sleeve with the fuel injection unit cylinder, a fuel supply pipe connected with said fuel injector unit cylinder, a piston reciprocable in said fuel injector unit cylinder and operating when moving in one direction to draw fuel thereinto from said pipe and when moving in the other direction to eject fuel through said valved passage into the sleeve beneath the plunger, and mechanism operatively coupled with said crank shaft for effecting timed movements of said body piston and plunger.

7. In a Diesel engine including a cylinder, a piston therein, and a crank shaft operatively coupled with the piston, means for introducing air into the cylinder when the piston is at the limit of its outward stroke, means for exhausting products of combustion from the cylinder when the piston is'at the limit of its outward stroke, a fuel injector unit comprising a body formed toprovide a sleeve and a cylinder, means for connecting an end of said sleeve with the interior of the engine cylinder, an injector plunger in said sleeve, a valved passage connecting said sleeve with the fuel injector unit cylinder, a fuel. supply pipe connected with said fuel injector unit cylinder, a piston reciprocable in said fuel injector unit cylinder and operating when moving in one direction to draw fuel thereinto from said pipe and when moving in the other direction to eject fuel through said valved passage into the sleeve beneath the plunger, mechanism operatively coupled with said crank shaft for effecting timed movements of the last-mentioned piston and plunger, said mechanism including a rockably supported bell crank, an oscillatable finger supported for'coaxial oscillation with said bell,crank and having one end in engagement cylinder fuel from said pipe, one arm of said bell crank when moved in one direction eifecting the movement of the said last-mentioned piston in opposition to said resilient means, cam means operated by said crank shaft, and a rodconnecting the other end of the bell crank with said cam for the cylinder, said ports being opened by the piston at the limit of its outward stroke, a fuel vaporizing chamber having one wall forming a part of the head of the cylinder and having communication with said fuel receptacle, and means for introducing vaporized fuel from the last chamber into the cylinder.

9. In an internal combustion engine of the type described, including a cylinder and piston operating therein, the cylinder being closed beneath the piston to form an air compression chamber, said piston being. hollow, means for conducting compressed air from said chamber, an air inlet port in the wall of the cylinder, a pair of ports opening through the wall of the cylinder and spaced longitudinally thereof, the pair of ports being ,in communication by Way of a passage in the body of the cylinder, said piston having two ports leading to the interior thereof, one piston port registering with said air inlet and the other piston port registering with the upper one of the pair of ports when the piston is at the limit of its inward movement, and the other one of the pair of ports opening into the cylinder below the piston when the piston is at the limit of its inward movement.

10. In an internal combustion engine of the type described, including a cylinder and a piston operating therein, means whereby said piston may be cooled during operation of the engine, which comprises providing the piston with a hollow interior and with a pair of apertures in the wall thereof opening into said interior, an air inlet port opening into the cylinder and arranged to register with one of said piston ports when the piston is at the limit of its inward movement, and a pair of ports in the wall of the cylinder having communication with one another and being spaced apart lengthwise of the cylinder, the upper one of the pair of ports being arranged to register with the other one of the piston ports when the piston is at the limit of its inward movement and the lower one of the pair of ports being arranged to admit air into the lower end of the cylinder beneath the piston when the latter is at the limit of its inward movement.

11. In an internal combustion engine of the character described, including a cylinder and a piston operating therein, means forming an air chamber within the wall of the cylinder having a port opening into the cylinder which is uncovered by the piston when the latter is at the limit of its movement outwardly, the lower part of the cylinder beneath the piston being closed to form a chamber in which air is compressed by the piston upon its outward movement, means for admitting air to the chamber for compression, a fuel receptacle, means for admitting air into the fuel receptacle from said air compression chamber, a fuel vaporizing chamber arranged to be heated by heat radiated from the wall of the cylinder, means for conducting fuel from the fuel receptacle into the vaporizing 10 

